Information searching in non-textual media is a fundamental point of interest, especially in the audiovisual industry where there is still an important need of tools for manipulating multimedia contents. In video documents, the style signature extraction is a highly interesting process since it provides a new feature for contents classification. Video documents may have very different characteristics and properties. However, we all agree that there are some common points between all political programs, or all football matches, or, time to time, between all the movies realized by a given director. These common points are what we call "invariants". An "invariant of production" characterizes a document or a set of documents belonging to a same "collection", of a same director, or produced following the same set of guidelines. In this paper, we present a hypothetical definition of what we call production invariant in a video segment. We propose an algorithm fo...